Method for designing mask and fabricating panel

ABSTRACT

A method for designing a mask and for fabricating a panel improves the efficiency with which a base substrate may be used by forming unit panels of different sizes on the base substrate. The mask includes a first region and a second region, a first mask pattern within the first region, and a second mask pattern within the second region.

This application is a divisional of application Ser. No. 10/602,672,filed Jun. 25, 2003, now U.S. Pat. No. 7,092,063, which claims priorityto Korean Patent Application No. 2002-0064061, filed Oct. 19, 2002, eachof which are incorporated by reference for all purposes as if fully setforth herein.

This application claims the benefit of the Korean Application No.P2002-64061 filed on Oct. 19, 2002, which is hereby incorporated byreference which is hereby incorporated by reference for all purposes asif fully set forth herein. This application incorporates by referencetwo co-pending application Ser. No. 10/184,096, filed on Jun. 28, 2002,entitled “SYSTEM AND METHOD FOR MANUFACTURING LIQUID CRYSTAL DISPLAYDEVICES” and Ser. No. 10/184,088, filed on Jun. 28, 2002, entitled“SYSTEM FOR FABRICATING LIQUID CRYSTAL DISPLAY AND METHOD OF FABRICATINGLIQUID CRYSTAL DISPLAY USING THE SAME”, as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to liquid crystal display (LCD) devices,and more particularly to a method of designing a mask and of fabricatinga unit panel while maximizing an efficiency with which a base substrateis used.

2. Discussion of the Related Art

Recent developments within the information communication field haveincreased demands for various types of display devices. In response tothis demand, flat panel displays such as liquid crystal display devices(LCDs), plasma display panels (PDPs), electro luminescent display(ELDs), and vacuum fluorescent display (VFDs) have been developed anduse as displays of various products.

Due to their excellent picture quality, light weight, thin profile, andlow power consumption, LCDs are used as televisions, capable ofreceiving and displaying broadcast signals, replacing cathode ray tubes(CRTs), and are widely used in portable displays such as monitors oflaptop and notebook computers, video cameras, and the like, that requiredisplays of different sizes.

Despite various technical developments in LCD technology, however,research in enhancing picture quality of LCD devices has been lackingcompared to research in other features and advantages of LCD devices.Therefore, to increase the use of LCD devices as displays in variousfields of application, LCD devices capable of expressing high qualityimages (e.g., images having a high resolution and a high luminance) withlarge-sized screens, while still maintaining a light weight, minimaldimensions, and low power consumption must be developed.

LCDs generally include a LCD panel for displaying a picture and adriving part for providing driving signals to the liquid crystal displaypanel. The LCD panel generally includes first and second glasssubstrates bonded to each other and spaced apart from each other by acell gap. A layer of liquid crystal material is injected into the gapbetween the first and second glass substrates.

The first glass substrate (i.e., thin film transistor (TFT) arraysubstrate), supports a plurality of gate lines spaced apart from eachother at a fixed interval and extending along a first direction; aplurality of data lines spaced apart from each other at a fixed intervaland extending along a second direction, substantially perpendicular tothe first direction, wherein pixel regions are defined by crossings ofthe gate and data lines; a plurality of pixel electrodes arranged in amatrix pattern within respective ones of the pixel regions; and aplurality of thin film transistors (TFTs) capable of transmitting signalfrom the data lines to corresponding ones of the pixel electrodes inresponse to a signal applied to respective ones of the gate lines.

The second glass substrate (i.e., color filter substrate) supports ablack matrix layer for preventing light leakage in areas outside thepixel regions; a color filter layer (R, G, B) for selectivelytransmitting light having predetermined wavelengths; and a commonelectrode for implementing a picture. In in-plane switching mode LCDdevices, the common electrode is formed on the first substrate.

Uniformity of the cell gap is maintained by spacers arranged between thefirst and second glass substrates, bonded together by a sealant. Thesealant includes a liquid crystal injection inlet allowing liquidcrystal material to be injected into the cell gap.

FIG. 1 illustrates a perspective view of a related art LCD panel in acolor LCD device.

Referring to FIG. 1, the related art LCD panel includes lower and uppersubstrates 1 and 2, respectively, that may be bonded together. A layerof liquid crystal material 3 is then injected between the bonded lowerand upper substrates 1 and 2.

The lower substrate 1 (i.e., the TFT array substrate) supports aplurality of gate lines 4 spaced apart from each other and extendingalong a first direction and a plurality of data lines 5 spaced apartfrom each other and extending along a second direction, substantiallyperpendicular to the first direction. Pixel regions P are defined bycrossings of the gate and data lines 4 and 5, respectively. A pluralityof pixel electrodes 6 are arranged in a matrix pattern within respectiveones of the pixel regions P and thin film transistors T are formed atcrossings of the plurality of gate and data lines 4 and 5, respectively.

The upper substrate (i.e., the color filter array substrate) supports ablack matrix layer 7 for preventing light leakage in areas outside thepixel regions P; a color filter layer (R, G, B) 8 for selectivelytransmitting light having predetermined wavelengths; and a commonelectrode 9 for implementing a picture.

Each of the thin film transistors T includes a gate electrode protrudingfrom a corresponding gate line 4, a gate insulating layer (not shown)formed over an entire surface of the lower substrate, an active layerformed on the gate insulating layer in a region above the gateelectrode, a source electrode protruding from a corresponding data line5, and a drain electrode formed opposite the source electrode. The pixelelectrode 6 is formed of a transparent conductive metal having goodlight transmittance characteristics such as indium-tin-oxide (ITO).

Still referring to FIG. 1, an orientation of molecules within the layerof liquid crystal material 3, provided between the lower and uppersubstrates 1 and 2, is adjusted by a signal output by the thin filmtransistor T. For example, a vertically oriented electric field,generated within the layer of liquid crystal material as a result of thesignal output by the thin film transistor T, adjusts the orientation ofmolecules within the layer of liquid crystal material. When theorientation of the liquid crystal molecules is adjusted, the lighttransmittance characteristics of the layer of liquid crystal material 3are affected. Accordingly, the signal output by the thin film transistorT enables the light transmittance characteristics of the layer of liquidcrystal 3 to be controlled while providing a pixel region P having ahigh aperture ratio. The common electrode 9 of the upper substrate 2 isgrounded, to prevent the pixel regions P from being electricallydamaged.

A method for fabricating the related art LCD panel shown in FIG. 1 willnow be explained in greater detail with reference to FIG. 2.

Referring to FIG. 2, a plurality of the aforementioned TFT arraysubstrates or color filter array substrates, both herein referred to asunit panels 12 are formed within a base substrate 11, wherein each unitpanel 12 is of the same size. Each unit panel 12 includes an activeregion 13, a black matrix region 14, and a pad region 15. Unit panels 12provided as TFT array substrates are fabricated via a plurality of thinfilm deposition and photolithography steps that incorporate the use ofmasks. After the unit panels 12 are formed, an inspection is performedto evaluate the quality of the unit panels 12, wherein the unit panel 12may be used in an LCD panel if the unit panel 12 is of a predeterminedquality.

After the unit panels 12 (e.g., TFT array substrates and color filtersubstrates) are formed within their respective base substrates 11, apolyimide alignment layer is printed onto a surface of the basesubstrates 11 and a heat treatment is then performed. Next, an alignmentdirection is imparted to the polyimide alignment layer via a rubbingprocess whereby the surface of the polyimide layer is rubbed with arubbing cloth. Accordingly, the rubbing process generates substantiallystraight alignment grooves on the surface of the polyimide alignmentlayer along a predetermined alignment direction. Next, the basesubstrates 11 are bonded together by a sealant provided at a peripheryof the active regions 13 of the unit panels 12, wherein the sealantincludes the liquid crystal injection inlet. Subsequently, the bondedunit panels 12 are separated from each other, liquid crystal material isinjected through the liquid crystal injection inlet and into the cellgap between the TFT array and color filter substrates, and the liquidcrystal injection inlet is sealed. Polarizing plates are formed onexternal surfaces of the bonded TFT array and color filter substratesand periphery circuits for driving the LCD panel are provided in the padregions, thereby completing the assembly of the related art LCD panel.

FIG. 3 illustrates a plurality of unit panels in one base substrate andFIG. 4 illustrates a mask used to form the unit panels shown in FIG. 3.

Referring to FIG. 3, four unit panels 12, having the same size, areformed within a base substrate 11 and are spaced apart from each otherby predetermined distances. When an intended size of the unit panels 12is smaller than an actual size of the mask 16 shown in FIG. 4, the unitpanels 12 may be designed by the mask 16. Accordingly, unit panels 12may be formed within the substrate 11 by applying various process stepsto portions of the base substrate 11 exposed by the mask 16, wherein themask is relocated over the base substrate 11 four times. When, however,the intended size of the unit panels 12 is larger than the actual sizeof the mask 16, the unit panels 12 cannot be designed using the mask 16.Accordingly, unit panels 12 having a size larger than a size of a maskcannot be designed and large-sized LCD panels cannot effectively bedesigned. In order to overcome the problem, the size of the unit panels12 must designed according to the size restrictions introduced by themask 16.

As mentioned above, LCD devices are being used in applications requiringLCD panels of diverse sizes. Generally, the size to which an LCD panelis fabricated depends upon the size of the apparatus fabricating the LCDpanel. Moreover, it is generally difficult to fabricate LCD panels ofvarying size in one fabrication processing line. Further, providing aplurality of fabrication processing lines, each suited to fabricate LCDpanel of a particular size are not feasible as apparatuses used tofabricate LCD panels tend to be expensive and take up large amounts ofspace.

To minimize the aforementioned problems, a plurality of unit panels 12,each having the same size, may be formed within a base substrate 11,wherein the size of each unit panel 12 is one-half, one-third,one-quarter, or even substantially the same size of the size of the basesubstrate 11. However, when the size of one unit panel within a basesubstrate is a large-sized panel (e.g., having dimensions of at least 30inches), other large-sized unit panels cannot be formed within theremaining portions of the base substrate. Accordingly, the efficiencywith which the base substrate is used becomes reduced and the price offabricating LCD panels increases.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a method for designinga mask and for fabricating a unit panel that substantially obviates oneor more problems due to limitations and disadvantages of the relatedart.

An advantage of the present invention provides a method for designing amask and for fabricating a unit panel capable of maximizing theefficiency with which a base substrate is used.

Another advantage of the present invention provides a method forfabricating a plurality unit panels within a base substrate, wherein theplurality of unit panels are not formed to the same size.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. These andother advantages of the invention will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, a methodfor designing a mask may, for example, include providing a mask to beapplied to a base substrate, wherein the mask is divided into a firstregion and a second region; designing a first mask pattern for formingat least one first unit panel within the first region; and designing asecond mask pattern for forming at least one second unit panel withinthe second region.

In one aspect of the present invention, the first mask pattern maycomprise a repeat region and a non-repeat region.

In another aspect of the present invention, the size of the first regionmay be substantially the same as the size of the second region.

In another aspect of the present invention, the size of the first regionmay be larger or smaller than the size of the second region.

In still another aspect of the present invention, the at least one firstunit panel may comprise a plurality of first unit panels.

In still another aspect of the present invention, the at least onesecond unit panel may comprise a plurality of second unit panels.

A method of fabricating a unit panel may, for example, include dividinga base substrate into a first region and a second region; forming atleast one first unit panel having a first size within the first region;and forming at least one second unit panel having a second size withinthe second region.

In one aspect of the present invention, an alignment direction impartedto the at least one first and second unit panels may be substantiallythe same.

In another aspect of the present invention, an alignment directionimparted to any of the at least one first and second unit panels may bedifferent.

In another aspect of the present invention, the at least one first unitpanel includes a plurality of first unit panels.

In still another aspect of the present invention, the plurality of firstunit panels may be formed by repeating the formation of the at the leastfirst one unit panel within the first region.

In still another aspect of the present invention, the at least onesecond unit panel includes a plurality of second unit panels.

In still another aspect of the present invention, the plurality ofsecond unit panels may be formed by repeating the formation of the atthe least one second unit panel within the first region.

In yet another aspect of the present invention, the at least one firstunit panel may be oriented at about 0°, 90°, 180°, or 270°, or any angletherebetween, with respect to the at least one second unit panel.

In still another aspect of the present invention, an alignment directionmay be imparted to any of the at least one first and second unit panelsvia a physical alignment process (e.g., a rubbing process) or via aphoto alignment process (e.g., a UV exposure process).

In yet another aspect of the present invention, the first and secondunit panels within the base substrate may be used to form LCD panels oflike liquid crystal modes or of different liquid crystal modes (e.g.,VA, IPS, TN, STN, and the like).

In a further aspect of the present invention, the first and second unitpanels within the same base substrate may used to form LCD panels havingthe substantially the same color reproduction ratios.

In yet another aspect of the present invention, the first size is largeror smaller than the second size.

In still another aspect of the present invention, a method forfabricating the unit panel may further include designating a pluralityof areas for inspection of the first and second unit panels ascoordinates; scanning an entirety of the first and second unit panels;and inspecting the plurality of areas designated as coordinates.

In yet another aspect of the present invention, a pitch of the firstunit panel may be different from a pitch of the second unit panel.

A method for fabricating a unit panel may, for example, includeproviding a mask, wherein the mask includes a first region and a secondregion, wherein the first region may include a repeat region and anon-repeat region, wherein the second region is smaller than the firstregion and includes the portions of the mask not included within thefirst region; and forming at least one first unit panel and at least onesecond unit panel on a base substrate using the mask.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 illustrates a perspective view of a related art LCD panel of acolor LCD device;

FIG. 2 illustrates the fabrication of a plurality of related art unitpanels of the same size in one base substrate;

FIG. 3 illustrates a plurality of related art unit panels having thesame size formed within the same base substrate;

FIG. 4 illustrates a related art mask used in forming the unit panelsshown in FIG. 3;

FIG. 5A illustrates a plan view of large-sized unit panel of a liquidcrystal display device (LCD) according to the present invention;

FIG. 5B is a plan view illustrating a method for designing a mask forforming a large-sized panel of FIG. 5A;

FIG. 5C is a plan view illustrating a method for designing a large-sizedpanel of FIG. 5A with a mask of FIG. 5B;

FIG. 6A and FIG. 6B are plan views illustrating a method for designing amask of a liquid crystal display device (LCD) according to anotherembodiment of the present invention;

FIG. 7A and FIG. 7B are plan views illustrating a method for designingpanels having various sizes with a mask of FIG. 6A and FIG. 6B;

FIG. 8 is a plan view illustrating a method for designing panels havingvarious sizes in a liquid crystal display device according to thepresent invention; and

FIG. 9A to FIG. 9D are exemplary views illustrating a state of forming aplurality of panels having different sizes according to the presentinvention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

FIG. 5A illustrates a plan view of a large-sized unit panel of a liquidcrystal display device (LCD) according to the present invention. FIG. 5Billustrates a plan view a method for designing a mask so as to form alarge-sized panel shown in FIG. 5A. FIG. 5C illustrates the fabricationof the large-sized panel shown in FIG. 5A using the mask shown in FIG.5B.

Referring to FIG. 5A, and as mentioned above, it is impossible tofabricate large-sized LCD panels with a single mask 23 when large-sizedunit panels 22 (e.g., TFT array or color filter substrates) used to formthe large-sized LCD panels (e.g., unit panels having a dimension of atleast 30 inches) are larger than the mask 23.

Therefore, as shown in FIG. 5B, when the size of the large-sized unitpanel 22 exceeds the size of the mask 23, the mask 23 may be dividedinto a plurality of portions. Accordingly, the mask 23, divided into theplurality of portions may then be used to form the large-sized unitpanel 22. For example, a center portion of the mask 23 may be providedas a repeat region 24 and first and second non-repeat regions 25 and 26,respectively, may be provided at left and right sides of the repeatregion 24 of the mask 23, respectively.

Referring to FIG. 5C, the large-sized unit panel 22 may be formed withina base substrate (not shown) using the first non-repeat region 25, therepeat region 24 twice, and the second non-repeat region 26. In oneaspect of the present invention, use of the repeat region 24 may berepeated any number of times as required depending on the size of therepeat region 24 and the size of the unit panel to be formed.

In one aspect of the present invention, the first non-repeat region 25of the mask 23 may be arranged over a region of the base substratecorresponding to a region to be occupied by a first portion of ablack-matrix region 32 and a first portion of a pad region 33 (e.g., theregion defined by region {circle around (1)} of FIG. 5A). In anotheraspect of the present invention, the second non-repeat region 26 of themask 23 may be arranged over a region of the base substratecorresponding to a region to be occupied by a second portion of theblack-matrix region 32 (e.g., the region defined by region {circlearound (2)} of FIG. 5A). In still another aspect of the presentinvention, the repeat region 24 of the mask 23 may be repeatedlyarranged over portions of the base substrate corresponding to a regionto occupied by a active region 31.

In one aspect of the present invention, when fabricating the large-sizedunit panel 22 using the mask 23 shown in FIG. 5B, various regions of thelarge-sized unit panel 22 (e.g., region {circle around (1)} region{circle around (2)}, the active region 31, etc.) may be aligned withalignment keys on corresponding portions of the mask 23 (e.g., firstnon-repeat region 25, second non-repeat region 26, repeat region 24,etc.) between various processing steps used to form the large-sized unitpanel 22. Referring to FIG. 5C, for example, the position of the of thefirst non-repeat region 25 may substantially correspond to the firstportion of the pad region 33 and black-matrix region 32 in region{circle around (1)}; the positions of the repeatedly arranged repeatregion 24 may correspond to adjacent areas of the active region 31, andthe position of the second non-repeat region 26 may substantiallycorrespond to the second portion of the black-matrix region 32 in region{circle around (2)}. In another aspect of the present invention, thelarge-sized unit panel 22 may be alternatively defined by the firstportion of the pad region 33 in region {circle around (1)} and an edgeof the active region 31 opposing region {circle around (1)} when thelarge-sized unit panel 22 does not include the second portion of theblack-matrix region 32.

In one aspect of the present invention, and as will be discussed ingreater detail below with respect to FIGS. 6A, 6B, 7A, and 7B, theaforementioned mask 23 may facilitate the formation of at least one unitpanel, smaller in size than the aforementioned large-sized unit panel22, within regions of the base substrate not occupied by theaforementioned large-sized unit panel 22.

FIGS. 6A and 6B illustrate plan views of a mask 23′ capable offacilitating the simultaneous formation of unit panels within a basesubstrate according to one aspect of the present invention.

Referring to FIGS. 6A and 6B, mask 23′ may be divided into first andsecond regions, wherein the first region includes a first mask pattern23 for forming unit panels such as the aforementioned large-sized unitpanel 22 (herein referred to as the first unit panel 22), and wherein athe second region includes a second mask pattern 27 for forming at leastone second unit panel, wherein the at least one second unit panel issmaller than the first unit panel 22. In one aspect of the presentinvention, the size of the first region may be substantially the same asthe size of the second region. In another aspect of the presentinvention, the size of the first region may be larger or smaller thanthe size of the second region. Accordingly, the first mask pattern 23used in formation of the first unit panel 22 may be included within mask23′ even when the first unit panel 22 is larger than mask 23′. Byproviding mask 23′ with the first and second regions, the efficiencywith which a base substrate is used in the formation of unit panels maybe maximized.

According to the principles of the present invention, the size of themask 23′ may be proportional to a vertical or horizontal dimension ofthe first unit panel 22. In one aspect of the present invention, thefirst mask pattern 23 may include the aforementioned repeat region 24and the non-repeat regions 25 and 26 as described with respect to FIGS.5A-5C for use in forming the first unit panel 22. Accordingly, therepeat and non-repeat regions of the first mask pattern 23 may bedivided and arranged within first region of the mask 23′. In one aspectof the present invention, the first and second non-repeat regions 25 and26 may be arranged at opposing sides of the repeat region 24 of thefirst mask pattern 23. In another aspect of the present invention, thefirst region may be arranged at a first side portion of the mask 23′ (asshown in FIG. 6A), at an upper portion of the mask 23′ (as shown in FIG.6B), etc. Further, the second mask pattern 27 may be arranged within thesecond region of the mask 23, wherein the second region includes theremaining areas of the mask 23′ not occupied by the first mask pattern23. In one aspect of the present invention, the second region may bearranged at a second side portion of the mask 23′ adjacent the firstside portion (as shown in FIG. 6A), at a lower portion of the mask 23′adjacent the first side portion (as shown in FIG. 6B), etc.

In one aspect of the present invention, the size and alignment directionof the at least one second unit panel may be different from the sizeand/or alignment direction of the first unit panel 22.

According to the principles of the present invention, as the anglebetween a user's eye and a display surface of an LCD panel changes, thenature and quality of an image displayed by the LCD panel, viewable bythe user, changes due to birefringence characteristics of liquid crystalmaterial within the LCD panel. As defined in the present invention, amain viewing angle may be defined as the viewing angle between obtainedwhen the brightest, clearest image is viewable from the LCD panel.Accordingly, and in one aspect of the present invention, the mainviewing angle of the at least one second unit panel may be differentfrom the main viewing angle of the first unit panel 22.

Further, the alignment process used to impart an alignment direction tothe at least one second unit panel may be different than the processused to impart the alignment direction to the first unit panel 22.

According to the principles of the present invention, an alignmentdirection may be imparted to any of the first and second unit panels byvia a physical alignment process (e.g., a rubbing process) or via aphoto alignment process (e.g., a UV exposure process). When, forexample, a rubbing process is used to impart an alignment direction to aunit panel, substantially straight alignment grooves may be formed on asurface of the unit panel, wherein the direction of the alignmentgrooves is determined by a rubbing direction of the rubbing process.Complementary ones of unit panels (e.g., TFT array and color filtersubstrates of an LCD panel) may be formed to have complementary (e.g.,different or same) alignment directions. After complementary ones of theunit panels are formed within their respective base substrates, they maybe bonded together to form the LCD panel. Upon bonding of thecomplementary substrates, the main viewing angle of the LCD panel isfixed.

FIGS. 7A and 7B illustrate plan views of unit panels fabricated usingthe first and second mask patterns illustrated in FIGS. 6A and 6B,respectively.

Referring to FIGS. 7A and 7B, a plurality of unit panels of differentsizes may be formed on a base substrate 21 using the mask 23′ shown inFIGS. 6A and 6B, respectively. For example, a first unit panel 22 may beformed within the base substrate 21 using the aforementioned first maskpattern 23 and at least one second unit panel 28, smaller than the firstunit panel 22, may be formed within regions of the base substrate 21 notoccupied by the first unit panel 22 using the second mask pattern 27(see FIGS. 6A and 6B). By forming a plurality of unit panels ofdifferent sizes within the same base substrate, the efficiency withwhich the base substrate 21 is used may be maximized. As shown in FIGS.7A and 7B, the first and second unit panels 22 and 28, respectively, maybe aligned with respect to each other at about 0° such thatcorresponding portions of the first and second unit panels may besimilarly oriented within the base substrate 21.

According to the principles of the present invention, the liquid crystalmode, main viewing angle, alignment direction, method by which thealignment direction is obtained, and color reproduction ratio of LCDpanels to be formed from complementary ones of the unit panels should beconsidered when forming the first and second unit panels within the basesubstrate 21. For example, while the unit panels of different sizes maybe formed within the same base substrate 21, alignment directions ofindividual ones of the unit panels 22 and 28 may be the same ordifferent.

In one aspect of the present invention, the first and second unit panels22 and 28, respectively, may have alignment directions that aresubstantially parallel to each other (i.e., an alignment direction ofthe first unit panel 22 is aligned at substantially 0° or 180° withrespect to an alignment direction of the second unit panels 28).Accordingly, the substantially parallel alignment direction may beprovided to the first and second unit panels in the same alignmentprocess via, for example, a physical alignment process (e.g., a rubbingprocess). During the rubbing process, the base substrate 21 is rubbedwith cloth attached to a rotating drum and substantially straightalignment grooves are formed within the first and second unit panels.The direction that the alignment grooves extend, and thus the alignmentdirection, depends upon the orientation of the cloth contacting the basesubstrate 21 during the rubbing.

According to the principles of the present invention, main viewingangles of LCD panels vary depending upon the particular application LCDpanels are used in. Further, main view angles of LCD panels depend uponthe alignment directions of their constituent complementary unit panelsas alignment directions of complementary unit panels influence theorientation characteristics of liquid crystal material within the LCDpanels. LCD panels formed including unit panels such as thoseillustrated in FIGS. 7A and 7B may have desirable viewing angles becausealignment directions of the complementary unit panels, formed withindifferent base substrates, may substantially complement each other(e.g., the alignment direction of a unit panel formed in one basesubstrate may complement the alignment direction of a complementary unitpanel formed in another base substrate). In one aspect of the presentinvention, main viewing angles of LCD panels may be adjusted byadjusting the alignment directions of the complementary unit panelsforming the LCD panel.

FIG. 8 illustrates a plan view of unit panels formed within a basesubstrate according to the principles of the present invention.

Referring to FIG. 8, a plurality of unit panels of different sizes maybe formed on a base substrate 21 using a mask (not shown) similar to themask 23′ shown in FIGS. 6A and 6B, respectively. In one aspect of thepresent invention, however, more than one first unit panel 22 may beformed within the base substrate 21 using a mask pattern provided in thefirst region of the mask while a plurality of second unit panels 28,smaller than the first unit panel 22, may be formed within regions ofthe base substrate 21 not occupied by the first unit panel 22 using amask pattern provided in the second region of the mask.

As mentioned above with respect to FIGS. 7A and 7B, the first and secondunit panels 22 and 28, respectively, may be oriented with respect toeach other at about 0° such that corresponding portions of the first andsecond unit panels may be similarly oriented within the base substrate21. Accordingly, a substantially parallel alignment direction may beprovided to each of the first and second unit panels 22 and 28 by theaforementioned physical alignment method.

As shown in FIG. 8, however, the first unit panels 22 may be aligned atangles other than 0° (e.g., 90°, 180°, 270°, or any other angletherebetween) with respect to the second unit panels 28. Formed via theaforementioned physical alignment process, LCD panels including the unitpanels shown in FIG. 8 as constituent complementary unit panels,however, may have undesirable viewing angles because alignmentdirections of the complementary unit panels, formed within differentbase substrates, may not properly complement each other (e.g., thealignment direction of a unit panel formed in one base substrate may notproperly compliment the alignment direction of a complementary unitpanel formed in another base substrate). Further, when first and secondunit panels 22 and 28 formed within a single base substrate 21 arerequired to have different alignment directions, use of theaforementioned physical alignment process can become problematic.

Accordingly, to overcome the aforementioned problems, the orientationcharacteristics of liquid crystal material to be provided within LCDpanels may be influenced by means other than the aforementioned physicalalignment process. In one aspect of the present invention, orientationcharacteristics of liquid crystal material may be influenced accordingto alignment directions provided via a photo alignment process (e.g., UVexposure process). In another aspect of the present invention,orientation characteristics of liquid crystal material may be influencedby forming the first and second unit panels 22 and 28 as constituentunit panels of VA mode LCD panels, capable of ensuring wide main viewingangles without employing the aforementioned alignment processes.

In performing the aforementioned photo alignment process, a desirablemain viewing angle in an LCD panel may be obtained because alignmentgrooves are not formed using a rotating drum to contact the entiresurface of the base substrate. In applying the photo alignment process,the surface of a unit panel may be selectively and uniformly exposed topolarized UV light via a lens and polarizer. Moreover, the UV light maybe irradiated onto the surface of the unit panel at a predeterminedangle. Accordingly, substantially straight alignment grooves may beformed only on portions of the substrate that were irradiated by the UVlight (e.g., only portions of the base substrate corresponding toindividual unit panels). Accordingly, alignment grooves extending alonga first predetermined direction may formed on first predetermined onesof unit panels by selectively irradiating first predetermined ones ofunit panels within the base substrate while the base substrate isoriented in a first orientation. Subsequently, alignment groovesextending along a second predetermined direction may be selectivelyformed on second predetermined ones of unit panels by selectivelyirradiating the second ones of predetermined unit panels within the basesubstrate while the base substrate is oriented in a second orientation.It will be appreciated that the principles of the present invention maybe used to form alignment grooves extending in any number of directions,wherein different unit panels may have different alignment directions,and wherein individual unit panels may include more than one alignmentdirection. Accordingly, by forming the first and second unit panels 22and 28 via photo alignment process, LCD panels having desirable viewingangles may be obtained even when unit panels 22 and 28 are formed withinthe base substrate at angles other than 0° with respect to each other.

TN mode LCD panels generally include a layer of liquid crystal materialhaving molecules with longitudinal directions that are substantiallyparallel with interior surfaces of complementary unit panels (e.g., TFTarray and color filter substrates) when a voltage is not applied to theLCD panel. Using any of the aforementioned alignment processes, apretilt angle may be induced within the liquid crystal molecules. Uponthe application of a voltage to the LCD panel, the longitudinaldirections of the liquid crystal molecules become substantiallyperpendicular with the surface of the unit panels. In VA mode LCDpanels, however, a protrusion and a slit may be formed on constituentunit panels to generate fringe electric fields. Accordingly, the fringeelectric fields may induce liquid crystal domains within a single pixelregion that maximize a main viewing angle without requiring use of anyof the aforementioned alignment processes.

In forming the aforementioned unit panels 22 and 28 as constituent unitpanels of VA mode LCD panels, longitudinal directions of liquid crystalmolecules within VA mode LCD panels may be substantially perpendicularto the interior surface of the complementary unit panels when a voltageis not applied to the LCD panel and when the liquid crystal material hasa negative dielectric anisotropy. Accordingly, when the voltage is notapplied to the LCD panel, voltage is not applied to the protrusion andliquid crystal molecules become substantially vertically aligned to aslope of the protrusion on the unit panel since the liquid crystalmolecules have tilt components. When voltage is applied to theprotrusion, different domains of different liquid crystal orientationchanges are induced within the layer of liquid crystal in accordancewith a boundary region between the protrusion and the slit. Accordingly,by forming the first and second unit panels 22 and 28 as constituentunit panels of VA mode LCD panels, an LCD panel having desirable viewingangles may be obtained even when unit panels 22 and 28 are formed withinthe base substrate at angles other than 0° with respect to each other.

In one aspect of the present invention, fabrication of unit panels maybe facilitated by forming unit panels intended to be constituentcomplementary unit panels within LCD panels of a single liquid crystalmode (e.g., TN, STN, IPS, VA, etc.) within the same base substrate. Forexample, TN mode LCD panels may include constituent complementary unitpanels that were all formed in the same base substrate and were allformed using the same processes. Accordingly, unit panels havingdifferent sizes and/or alignment directions (e.g., alignment groovesextending along different directions), and intended to be constituentcomplementary unit panels within LCD panels of a single liquid crystalmode may be formed within the same base substrate. In another aspect ofthe present invention, however, unit panels intended to be formed in LCDpanels of different liquid crystal modes may also be formed within thesame base substrate. For example, a unit panel intended to be aconstituent unit panel of a IPS mode LCD panel may be formed within thesame base substrate as a unit panel intended to be a constituent unitpanel of a STN mode LCD panel is formed within. In yet another aspect ofthe present invention, unit panels intended to be formed within LCDpanels having the substantially the same or similar color reproductionratio may be formed within the same base substrate.

As described above, a plurality of unit panels of the same or differentsize, and having the same or different alignment directions, may beformed within a single base substrate. Accordingly, the efficiency withwhich a base substrate is used may be maximized. Further, the unitpanels within the base substrate may be aligned at substantially anyangle with respect to each other. Further, formation of the first and/orsecond unit panels 22 and/or 28, respectively, may be repeated withinthe first and/or second respective regions of the base substrate,respectively. Still further, the unit panels may be symmetrically orasymmetrically arranged about an axis of the base substrate. In oneaspect of the present invention, the symmetrical arrangement of the unitpanels may facilitate photo alignment, physical alignment, inspecting,and other processes used in forming the unit panels (e.g., the TFT arrayand/or color filter substrates). In one aspect of the present invention,the photo alignment method may employ a mask having a size that issubstantially equal to, or greater than, the size of the unit panelbeing exposed. In another aspect of the present invention, the size ofthe mask used in the photo alignment method may be smaller than the sizeof the unit panel and may be used to repeatedly form unit panels forimproving yield.

According to the principles of the present invention, an inspectingprocess may be performed to inspect the unit panels formed within thebase substrate 21. In one aspect of the present invention, the unitpanels may be inspected by designating one or more areas on the basesubstrate for inspection and assigning coordinates to the areas to beinspected. Accordingly, it may not be necessary for the unit panels tobe symmetrically arranged within the base substrate 21 in order toperform the inspection process. In another aspect of the presentinvention, the unit panels may be repeatedly formed within the basesubstrate to facilitate the inspection process.

According to the principles of the present invention, an alignmentdirection may be provided to unit panels symmetrically arranged within abase substrate by, at least in part, printing an alignment layer madeout of a material such as polyimide onto a surface of the unit panel. Inone aspect of the present invention, alignment layers having sizescorresponding to the sizes of unit panels asymmetrically arranged withinthe base substrate may be applied to regions of the base substratecorresponding to particular unit panels. Thus, unit panelsasymmetrically arranged within the base substrate may be repeatedlyformed within the base substrate for improving yield. In one aspect ofthe present invention, alignment grooves may be formed by applying theaforementioned alignment processes to the alignment layer.

Upon inspecting the unit panels formed within the base substrate (e.g.,the first unit panels, the second unit panels, or both), an area to beinspected may be assigned specific coordinates. In one aspect of thepresent invention, the assigned areas may be inspected. In anotheraspect of the present invention, the entire area of the base substratemay be scanned during the inspecting.

As described above, the principles of the present invention provide asingle mask that is designed to allow unit panels of differing sizes tobe formed within the same base substrate. However, in another aspect ofthe present invention, the at least one first unit panel 22 and the atleast one second unit panel 28 may be formed using separated first andsecond masks, respectively. Accordingly, the aforementioned repeatregion 24 and first and second non-repeat regions 25 and 26,respectively, may be included within the first mask while the secondmask may be used to form the second unit panels.

FIGS. 9A to 9D illustrate views of a method of forming panels havingdifferent sizes according to the present invention.

Referring to FIG. 9B, the first unit panel 22 shown in FIG. 9A (e.g., aunit panel such as the aforementioned large-size unit panel) may beconceptually divided into portions corresponding to a first non-repeatregion 25, two adjacent repeat regions 24, and a second non-repeatregion 26. Subsequently, as shown in FIG. 9C, a first mask patternhaving mask regions used to form the conceptually divided portions ofthe first unit panel 22 may be arranged in a side portion or an upperportion of mask 23″. Further, a second mask pattern 27 used to form atleast one second unit panel 28 may be arranged within a remainingportion of the mask 23″.

Referring to FIG. 9D, the first unit panel 22 and a plurality of secondunit panels 28, smaller than the first unit panel 22 may be formedwithin the same base substrate 21 using the mask 23′ designed as shownin FIG. 9C.

The method for designing a mask and of fabricating the unit panelsaccording to the present invention is advantageous because a pluralityof unit panels having different sizes may be formed on the same basesubstrate, thereby improving the efficiency with which the basesubstrate is used and reducing a manufacturing cost of LCD panels.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A method of designing a mask, comprising: applying a liquid crystaldisplay unit panel mask to a base substrate, the liquid crystal displayunit panel mask including a first region and a second region; providinga first mask pattern within the first region, the first mask pattern forforming at least one first unit panel within the base substrate; andproviding a second mask pattern within the second region, the secondmask pattern for forming at least one second unit panel within the basesubstrate, wherein the at least one second unit panel is formable to adifferent size than the at least one first unit panel, wherein the atleast one first unit panel is larger than the first mask pattern.
 2. Themethod of claim 1, further comprising dividing the first mask patterninto a repeat region and a non-repeat region.
 3. The method of claim 1,wherein a size of the first region is substantially the same as the sizeof the second region.
 4. The method of claim 1, wherein a size of thefirst region is greater than a size of the second region.
 5. The methodof claim 1, wherein a size of the first region is less than a size ofthe second region.
 6. The method of claim 1, wherein the at least onefirst unit panel includes a plurality of first unit panels.
 7. Themethod of claim 1, wherein the at least one second unit panel includes aplurality of second unit panels.
 8. The method of claim 1, wherein thesecond region is arranged in portions of the mask not occupied by thefirst region.